1. Field of the Invention
The present invention pertains to the temporary covering of a relatively large land area with flexible synthetic sheets.
2. Description of Related Art
It is frequently desired to cover a relatively large land area to keep the area dry and protected from rainfall, dew and the like, and also to prevent wind erosion of the land surface. Land areas may, for example, be used for sanitary landfill sites. Due to environmental and other sanitary concerns, operators of sanitary landfill sites have been required to provide a daily cover for sanitary landfill deposited during the course of the workday. According to currently accepted and environmentally mandated practices, a soil cover of a guaranteed six inch minimum depth is usually employed. The manpower required to deploy and recover the daily soil cover is very substantial, up to one fourth of a workday being devoted to working with the soil cover. Considerable cost savings could be realized if an alternative to the daily soil cover were available or if the rate of consumption of the soil cover or the very substantial amount of manpower required for its use could be reduced.
During the course of developing a sanitary landfill site, portions of the site remain undisturbed for relatively long periods of time while other portions of the site, located at the working area, need to be cleared of the soil cover at the beginning of each workday. It has been observed that, due to the porous nature of the sanitary landfill site the amount of soil cover consumed daily in this manner comprises a considerable portion of the total soil cover required. At some landfill sites a daily soil cover is not available and must be purchased from an outside source at considerable expense. In addition, the soil cover consumed each day results in a premature filling of the landfill site and constitutes an inefficient use of the site for its intended purpose.
Other areas of commercial endeavor are concerned with the covering of relatively large land areas. U.S. Pat. No. 3,727,656, for example, discloses foldable flexible synthetic plastic sheets for covering a grain stockpile. The flexible sheet material is constructed to form a flexible, balloon-like container which is enlarged as grain is poured therein. U.S. Pat. No. 975,802 discloses a stack cover used to protect hay and grain stacks. The temporary structure is formed from metal panels which are joined together at the corners of the structure.
In addition to agricultural applications, it is frequently desirable to cover athletic playing fields and U.S. Pat. Nos. 1,576,888; 2,578,135; and 2,848,233 disclose arrangements of partially overlapping flexible sheets which are joined together using rope or the like to form a large-size integrated covering system
In other commercial applications, various arrangements have been employed to cover waste materials, whether stored in containers or deposited in a landfill site. U.S. Pat. No. 3,874,175 discloses a floating cover assembly used, in cooperation with a lined pit, to contain animal and livestock waste. U.S. Pat. No. 4,519,338 discloses a hardenable plastic foam to cover and seal a landfill or dump area. A vehicle having foam spray apparatus traverses back and forth over the dump area to form an integrated seal, obviating the need for a soil cover of compacted earth.
U.S. Pat. No. 1,871,571 discloses a tarpaulin of waterproof reinforced paper. The borders of the tarpaulin are reinforced with layers of sisal to afford reinforcement at a point of grommet attachments. U.S. Pat. No. 4,565,468 discloses a moisture barrier in which a layer of bentonite is disposed between opposing, overlying sheets stitched together in a quilting pattern.
A need still exists for simple and economical method and apparatus for providing a temporary daily cover for a large land area and in particular for covering a relatively large sloping land area to prevent moisture intrusion and wind erosion.
Turning now to the construction industry in general, it is sometimes more economical to form very large structures with the largest possible components that can be handled in a practical manner. U.S. Pat. No. 3,552,583 discloses a system for erecting a building structure by lifting a pair of curved wall sections which are pivotally supported at the ends of a beam. When the beam is raised, the panels may be swung into a mutually self-supporting position. As another example, U.S. Pat. No. 2,347,922 discloses a hoisting tong used to grasp and lift heavy metal plates and the like. As a further example of special limited use equipment, U.S. Pat. No. 4,159,059, provides a truss boom for a material-handling truck having what is commonly referred to as a "stinger arm", comprised of a series of telescoping sections which extend and retract to move a load carried at the end of the arm.
One type of construction machine in common use today is a front loader or bucket loader, used to transfer bulk materials from one location to another. Frequently, it is desired to adapt the bucket loader to lift or lower relatively massive discrete objects. For example, U.S. Pat. No. 4,200,423 discloses a storable boom mounted to the bucket of a construction machine, adapting the machine for lifting and lowering of objects in construction work. The boom is telescopically inserted in a pair of mounting brackets attached to a base plate which is welded to a top side of the bucket.
U.S. Pat. No. 4,329,103 discloses a framework attachment received in the bucket of a front-end loader to provide a boom structure device having a forwardly extending beam. U.S. Pat. No. 2,613,912 discloses a framework rig attachable to the bucket of a bulldozer or the like. The rig is used to set and pull fence posts. U.S. Pat. No. 3,587,887 is directed to a lifting boom consisting of three pivotally connected arms attached at the top and bottom walls of the bucket, which is used to lower a pipe into a trench, for example.
A need still exists, however, for a simple boom-like apparatus which adapts a front-end loader for lifting relatively large and/or heavy objects. In particular, there is a need to provide an apparatus of this type which is quickly and easily installed and removed from a conventional front-end loader on a frequent basis, such as several times a day.